In static charge reduction technical field, a humid air stream generator is used to increase the humidity of the air for reducing static charge. In a known air stream controller, the humid air stream for static charge reduction after released from the outlet tubing for use in static charge mitigation is channeled as a returned loop back into the humidifier chamber of the humid air stream generator for re-circulation to achieve better air flow control for optimum output. This closed-loop system not only helps to prevent or minimize the leakage of the humid air into the surrounding ambient environment, it also cuts the wastage of humid air and contributes to an optimum amount of humid air to be produced economically.
FIG. 1 comprises shown a common known humid air stream generator 1 having a main chamber attached with an inlet tubing 12 for feeding dry air and an outlet tubing 19 for outputting moist air. A mist generator 11 is arranged at the bottom of the chamber.
However, during the running of the air stream controller at a relative humidity (RH) especially at above 80%, water condensation was seen on the walls 14 of the chamber and on the inner walls of the outlet tubing 19 as illustrate in FIG. 1.
These tiny droplets accumulate to form bigger drops 13 and subsequently dripping down the walls 14 causing accumulation of water, especially inside the outlet tubing 19 causing unwanted trapping and retention of water inside the tubing. This is undesirable in the management and control of humid air for static charge mitigation in the air flow control system.
It is interesting to discover that putting a mini heater in the air flow path at the region above the mist generator 11 helps to minimize or eliminate such unwanted condensation especially at a level above 80% RH. In fact, up to the 85% to 90% RH range, there is no condensation being seen both at the walls of the outlet air flow region as well as at the inner circular wall of the air circulation tube when the mini heater is switched on. The higher the heater temperature, the lesser the condensation is seen on the walls.
However, careful analysis reveals that the heater not only involves installation work, close monitoring, safety issue and additional cost to the system, it also cause contamination issue after long period of uses due to the oxidation or corrosion, pre-matured wear and tear and dirt accumulation issues using such heater system.
Therefore further research and development work is needed to search for a better and easier way to overcome such condensation problem without design pitfalls and shortcomings.